Are the chicks ok?

When I went to my friends house Jack, he had some 5-6 week old RIRs and BR. They looked nothing like my 5 week old soon to be six week olds. I asked him if he was SURE that they were 5-6 week old, and he said he was positive. Are my chickens not really 5 weeks old? (I bought them when they were 2 days old.) Please answer this.

Yes I'd say they look about right. What did his look like? More feathered? Less?

The temp he kept them in might have something to do with that. I read somewhere that cooler temps (within the chicks' comfort zone) = earlier feathering, while warmer temps tend to delay the feathering a bit.

That makes sense. I've been told mine look older than 4 and 5 weeks because they are nearly fully feathered, but I also moved mine into the coop and run about two weeks ago and I have a heat lamp in there for the cool nights.